Lull 844 Cylinder Issues: Causes and Solutions

[MikePhua]

The Lull 844, a versatile telehandler often used in construction, industrial, and agricultural applications, is known for its impressive lifting capabilities and reach. However, like any heavy machinery, it is prone to mechanical issues, particularly with its hydraulic system. One common issue owners and operators face is problems with the hydraulic cylinders, which can affect the lifting performance and overall efficiency of the machine. This article will delve into the potential causes of hydraulic cylinder failure on the Lull 844 and offer guidance on troubleshooting and repairs.
Understanding the Lull 844 and Its Hydraulic System
The Lull 844 telehandler, manufactured by JLG Industries, is part of the Lull family of rough terrain forklifts and telehandlers. This machine is designed to lift heavy loads to considerable heights, making it ideal for tasks in construction sites, warehouses, and agricultural fields. The 844 is equipped with a hydraulic system that powers various functions, including the boom lift and extension, and supports the lifting and lowering of materials.
The hydraulic cylinders are crucial components in this system, as they convert hydraulic pressure into mechanical force to move the machine’s boom. These cylinders are subjected to significant stress during normal operation, making them prone to wear and potential failure if not properly maintained.
Common Issues with Lull 844 Hydraulic Cylinders

1. Cylinder Leaks
   Hydraulic fluid leaks are one of the most common issues with hydraulic cylinders. A leak in the cylinder seals or piston rings can result in a loss of pressure, which impairs the functionality of the lifting mechanism. Leaks often occur due to wear and tear on the seals, exposure to harsh environments, or poor maintenance practices.
   
2. Damaged or Worn Seals
   The seals on hydraulic cylinders are responsible for preventing fluid from escaping and ensuring that the cylinder operates smoothly. Over time, seals can degrade due to heat, friction, or chemical exposure, causing fluid to leak out. Worn seals can lead to sluggish or erratic cylinder movement and, if left unaddressed, could cause the cylinder to fail completely.
   
3. Cylinder Scoring or Pitting
   The piston rod of the hydraulic cylinder moves in and out of the cylinder barrel, and if there is any debris or contamination in the hydraulic fluid, it can cause scoring or pitting on the piston rod surface. This damage can interfere with the cylinder’s smooth operation and lead to leaks or total failure of the cylinder.
   
4. Hydraulic Fluid Contamination
   Contaminated hydraulic fluid is a major cause of failure in hydraulic systems. Dirt, water, or other contaminants can enter the hydraulic fluid, leading to increased wear on cylinder seals, pistons, and other components. Contamination may also cause the hydraulic fluid to lose its lubricating properties, which can lead to overheating and breakdowns.
   
5. Improper Cylinder Alignment
   Misalignment of the hydraulic cylinder can put undue stress on the cylinder components, leading to accelerated wear. Misalignment can result from improper installation, damage to the cylinder mounting points, or structural issues in the telehandler's frame. This misalignment can cause uneven load distribution and hinder the cylinder’s ability to extend or retract smoothly.
   
6. Overloading and Excessive Force
   Overloading the Lull 844 or using it beyond its rated capacity can put extreme stress on the hydraulic cylinders. Excessive force, particularly when lifting heavy loads or extending the boom to its maximum reach, can cause damage to the seals, rods, and internal components of the cylinder. Operating beyond the machine’s limits can also lead to catastrophic failure if not monitored.
   

Troubleshooting Hydraulic Cylinder Issues on the Lull 844
If you encounter issues with the hydraulic cylinders on your Lull 844, the following steps can help diagnose and fix the problem:

1. Check for Leaks
   Inspect the hydraulic cylinders for visible signs of fluid leakage. Leaks may appear around the piston rod, cylinder body, or at the cylinder seals. Clean the area around the cylinder and run the telehandler to check for active leaks. If you notice any, you will need to replace the seals or gaskets, or in more severe cases, the entire cylinder assembly.
   
2. Inspect Seals for Wear
   Look for cracks, tears, or other signs of damage on the seals. If the seals are worn, replacing them is usually the most straightforward solution. However, it’s essential to check if the piston rod is damaged, as this could cause new seals to fail prematurely.
   
3. Check for Scoring or Pitting on the Piston Rod
   Run your fingers along the surface of the piston rod to feel for any rough spots or grooves. If you notice scoring or pitting, the piston rod may need to be replaced or refurbished. In some cases, the rod can be polished if the damage is minor, but severe damage will likely require a full replacement.
   
4. Test for Hydraulic Fluid Contamination
   Drain the hydraulic fluid and inspect it for signs of contamination. Contaminated fluid may appear discolored, milky, or cloudy, indicating the presence of water or dirt. Replace the fluid with clean hydraulic oil and flush the system to remove any remaining contaminants. Installing better filtration systems can help prevent contamination in the future.
   
5. Inspect Cylinder Alignment
   Check the alignment of the hydraulic cylinder in relation to the boom arm and mounting points. If the cylinder appears misaligned, inspect the mounting brackets and other structural components for damage or wear. Misalignment often requires realignment or replacement of mounting components to restore proper function.
   
6. Avoid Overloading the Machine
   Always ensure that the Lull 844 is operating within its recommended weight limits. Overloading the machine can cause premature failure of the hydraulic cylinders. Review the operator’s manual to ensure that the load being lifted is within the safe operating range.
   

Repairing or Replacing Hydraulic Cylinders on the Lull 844
If your troubleshooting efforts indicate that the hydraulic cylinder cannot be repaired, it may need to be replaced. Here are some steps for replacing a hydraulic cylinder:

1. Disassemble the Cylinder
   Begin by removing the cylinder from the telehandler. This typically involves disconnecting the hydraulic lines and unbolting the cylinder from the frame or boom. Take care to drain any remaining hydraulic fluid from the system before disassembly.
   
2. Remove the Damaged Components
   Carefully remove the piston rod, seals, and other damaged components. Be sure to note the order of the parts to ensure proper reassembly later.
   
3. Install the New Cylinder or Components
   If replacing the entire cylinder, install the new one in the same position as the old unit. If only the seals or piston rod need replacing, carefully install the new parts and reassemble the cylinder.
   
4. Reassemble and Test the System
   Once the cylinder is replaced or repaired, reattach it to the machine, reconnect the hydraulic lines, and fill the system with fresh hydraulic fluid. Test the machine to ensure the new cylinder is functioning correctly, and monitor for leaks or irregular performance.
   

Preventive Measures to Avoid Cylinder Issues

1. Regular Inspection and Maintenance
   Perform routine checks of the hydraulic system, including the cylinders, seals, hoses, and fluid levels. This helps identify potential problems before they escalate into serious issues.
   
2. Use Proper Hydraulic Fluid
   Always use the correct type and grade of hydraulic fluid for the Lull 844. Using subpar or incompatible fluid can lead to contamination, overheating, and damage to the hydraulic system.
   
3. Avoid Overloading
   Follow the manufacturer’s guidelines for safe lifting capacities and avoid overloading the machine. Excessive weight can place unnecessary strain on the hydraulic system and cause premature cylinder failure.
   
4. Install Additional Filtration
   Consider adding better filtration systems to the hydraulic system to prevent contamination and extend the life of the hydraulic components.
   

Conclusion
Hydraulic cylinder issues on the Lull 844 telehandler can cause significant disruptions to worksite operations. Identifying and resolving these problems early through regular maintenance, proper fluid checks, and timely repairs can help avoid costly downtime and extend the machine’s lifespan. By understanding the causes of hydraulic cylinder failures and following the recommended troubleshooting and repair steps, operators can keep their Lull 844 performing efficiently for years to come.